Application Design (was Re: Testing the waters.)

Adam Alpern alpern@ns2.brightware.com
Fri, 9 May 1997 11:06:54 -0700


Chris Bitmead:
;; If you have a POS, you will want to write all your algorithms without
;; thinking about the disk. If you move to a non-POS environment you

I write my algorithms without thinking about the disk anyway, unless I
happen to be writing applications that deal with huge amounts of
data. Then, I try to be careful not to write code that will cause page
thrashing. If some of your objects are in memory and some are on disk,
and you don't care, you're going to thrash the disk.

;; would have to load all objects into memory up front before setting
;; your algorithms into action. This is of course an appalling waste of
;; memory.

And operating directly on disk-based objects is an appalling waste of
time. 6 of one...

;; Alternatively you can pollute your entire source code with file
;; handling stuff. Very ugly by comparision.

You seem to want to force the world into your view that not having a
POS means the ENTIRE APPLICATION gets written differently. I don't
know how you came to be of this opinion, but if you think that using
regular files means you have to "pollute your entire source code with
file handling stuff", then I don't ever want to use your code.

In my last message I mentioned how I converted an app from using flat
ASCII files for persistence to using a persistent heap. 

NOT ONE LINE OF THE MAIN APPLICATION CHANGED. All I did was redirect a
few high-level methods like #'save-object and #'load-object.

Adam